Max front wheel size and offset for 69' Cuda w/ BB and chassis exit headers

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Hemioutlaw

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My Car: 69' Barracuda Fastback with 440 and 1 3/4 Chassis exit TTI's

Hey y'all, I'm back again,
Just swapped out my fenderwells for chassis exit and got rid of the KH and went to the later Single piston calipers and 5 x 4 1/2 BP so I can finally get a bigger front tire on the car...Shopping now for some Steelies or Police wheels and wondering what the Max front wheel size is that I can use and what wheel offset is required.

I have no wheels here to mock it up so need to get it right when I order wheels, I'm thinking a 15 x 6 but see that they are available in many different offsets and don't know which is the correct one to use.

Any help on correct wheel offset or even pointing to a past thread on the subject would be immensely appreciated...Thx
 
Stock factory offset for the BBP disk brake wheels was +6. That’s a 15x7 with a 4.25” backspace (cop wheels) or a 15x6 with a 3.75” backspace.

With a 15x7 and 4.25” of backspace you can run up to about a 225/60/15 without permanent modifications. With a Barracuda the wheel opening is a little limiting, the front lower corner of the fender gets in the way if you go too tall with the tires. You definitely want to stay under 26” tall unless you’re running really skinny tires.

But with 15’s I’d stay with 15x7’s and nothing bigger than a 225/60/15 unless you want to modify stuff.
 
Stock factory offset for the BBP disk brake wheels was +6. That’s a 15x7 with a 4.25” backspace (cop wheels) or a 15x6 with a 3.75” backspace.

With a 15x7 and 4.25” of backspace you can run up to about a 225/60/15 without permanent modifications. With a Barracuda the wheel opening is a little limiting, the front lower corner of the fender gets in the way if you go too tall with the tires. You definitely want to stay under 26” tall unless you’re running really skinny tires.

But with 15’s I’d stay with 15x7’s and nothing bigger than a 225/60/15 unless you want to modify stuff.

You are the man NBLU, thank you so much for your reply
 
Stock factory offset for the BBP disk brake wheels was +6. That’s a 15x7 with a 4.25” backspace (cop wheels) or a 15x6 with a 3.75” backspace.

With a 15x7 and 4.25” of backspace you can run up to about a 225/60/15 without permanent modifications. With a Barracuda the wheel opening is a little limiting, the front lower corner of the fender gets in the way if you go too tall with the tires. You definitely want to stay under 26” tall unless you’re running really skinny tires.

But with 15’s I’d stay with 15x7’s and nothing bigger than a 225/60/15 unless you want to modify stuff.

Mr. 72bluNblu or ?,
After striking out at a few local wrecking yards, I'm literally about to order these wheels in the Cop style right now and I'm pleading ignorance on the subject but this has been knawing at me a bit and just out of curiosity is there a benefit or reason to prefer the 15 x 7 over the 15 x 6 wheels since the 225/60/15 tires will fit on a 6-7.5" rim. Just looking for an opinion---Thx
 
Mr. 72bluNblu or ?,
After striking out at a few local wrecking yards, I'm literally about to order these wheels in the Cop style right now and I'm pleading ignorance on the subject but this has been knawing at me a bit and just out of curiosity is there a benefit or reason to prefer the 15 x 7 over the 15 x 6 wheels since the 225/60/15 tires will fit on a 6-7.5" rim. Just looking for an opinion---Thx

The 225/60/15's will be slightly less squeezed on the 15x7's. They will fit on a 15x6", but the narrower rim tends to push the center of the tread patch up a little bit because the sidewalls are squeezed closer together.

It won't be a huge difference but you should get slightly better performance out of a 225/60/15 on a 7" rim than you would on a 6". Not saying you'll actually notice that difference because it will be really minor, but that's the idea. If I were buying new rims with that tire size in mind I'd buy 15x7's. If I already had a set of 15x6's I wouldn't worry about it.
 
The 225/60/15's will be slightly less squeezed on the 15x7's. They will fit on a 15x6", but the narrower rim tends to push the center of the tread patch up a little bit because the sidewalls are squeezed closer together.

It won't be a huge difference but you should get slightly better performance out of a 225/60/15 on a 7" rim than you would on a 6". Not saying you'll actually notice that difference because it will be really minor, but that's the idea. If I were buying new rims with that tire size in mind I'd buy 15x7's. If I already had a set of 15x6's I wouldn't worry about it.

What a logical explanation, Once again I offer my supreme gratitude.

I had thought that because my application was a 69' Cuda which has it's own inherent wheel well limitations that perhaps it would be more prudent to go with the 15 x6 but honestly didn't know.
 
What a logical explanation, Once again I offer my supreme gratitude.

I had thought that because my application was a 69' Cuda which has it's own inherent wheel well limitations that perhaps it would be more prudent to go with the 15 x6 but honestly didn't know.

Ok, so, I was working under the assumption that both wheels used the same offsets. The factory cop wheels were 15x7 and have 4.25" of backspace (+6 offset). I see now that the wheel vintiques reproduction 15x7's only list a 4" backspace (0 offset) while the 15x6's have a 3.75 backspace (+6 offset).

You need a +6 offset to pull off the 225's. So, I would actually use the 15x6's if you're buying the wheel vintiques. It's really dumb that the 15x7" wheel vintiques have a 4" backspace, the factory used 4.25" for a reason. Sorry about the confusion. If the offsets were the same I'd use the 7's all day long.
 
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Ok, so, I was working under the assumption that both wheels used the same offsets. The factory cop wheels were 15x7 and have 4.25" of backspace (+6 offset). I see now that the wheel vintiques reproduction 15x7's only list a 4" backspace (0 offset) while the 15x6's have a 3.75 backspace (+6 offset).

You need a +6 offset to pull off the 225's. So, I would actually use the 15x6's if you're buying the wheel vintiques. It's really dumb that the 15x7" wheel vintiques have a 4" backspace, the factory used 4.25" for a reason. Sorry about the confusion. If the offsets were the same I'd use the 7's all day long.
Johnny-Carson Kreskin.jpg
Ha Ha Ha..Too Funny!
Well call you Psychic, the Amazing Kreskin's got nothing on you..Lol
Was just about to post about the Wheel Vintiques quandary and the 4" backspace, I was actually thinking of going with the 215/60/15's on a 15 x 6 just so I wouldn't have any interference problems.

Do I dare ask another question.....The 15 x 10 Fenton Gyro rears I'm replacing have got a bastard backspace as well (3 1/4") so Vintiques will have to custom make those for me in the police wheel style. I'm wondering if you have any tire Manufacturer style recommendations for the front's...I see that many have the Cooper Cobra's and I like the look but have no experience with them but then it's all a moot point since they aren't offered in a 215 or 225/ 60 anyway...TA's are offered in both sizes but BFG is proud of them. Probably going to keep slicks on the Gyro's for a track only spare set but unsure what street type tires to run on the rears, I do know that I'm not a young man anymore and don't want to be replacing the rears every year if I can help it so also looking for a midgrade compound tire.
 
View attachment 1715676224 Ha Ha Ha..Too Funny!
Well call you Psychic, the Amazing Kreskin's got nothing on you..Lol
Was just about to post about the Wheel Vintiques quandary and the 4" backspace, I was actually thinking of going with the 215/60/15's on a 15 x 6 just so I wouldn't have any interference problems.

Do I dare ask another question.....The 15 x 10 Fenton Gyro rears I'm replacing have got a bastard backspace as well (3 1/4") so Vintiques will have to custom make those for me in the police wheel style. I'm wondering if you have any tire Manufacturer style recommendations for the front's...I see that many have the Cooper Cobra's and I like the look but have no experience with them but then it's all a moot point since they aren't offered in a 215 or 225/ 60 anyway...TA's are offered in both sizes but BFG is proud of them. Probably going to keep slicks on the Gyro's for a track only spare set but unsure what street type tires to run on the rears, I do know that I'm not a young man anymore and don't want to be replacing the rears every year if I can help it so also looking for a midgrade compound tire.

Dont forget , if ur car has the front lower fender braces , u can make longer ones to shove the front lower edge out some , w/o messing anything up.
 
Dont forget , if ur car has the front lower fender braces , u can make longer ones to shove the front lower edge out some , w/o messing anything up.

Except it’s a barracuda. They don’t have those lower fender braces.
 
Except it’s a barracuda. They don’t have those lower fender braces.

My new 68 fastback formula S had them , this basket case I rebuilt didnt , but has places to bolt them on to --------??
 
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